Luther's concept of Christian life has influenced the reformed church right up to the present day. In this study on church history, Andreas Stegmann presents the genesis and structure of Luther's ethics on the basis of his complete works and within the context of reformation history. The book is divided into four parts and deals with Luther's late medieval background, the development of his concept of Christian life between 1513 and 1519, the defining formulation of the main ideas behind reformation ethics of 1519/20 and the further unfolding of these and their compounding since the 1520s. In particular, special attention is paid to the religious dimension of Luther's ethics, which is shaped by the existential communion with Christ and leads to an embrace of this world grounded in the justificatory faith.